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QuickTime Department of Apple's playback software for Apple series of compressed formats, such as video mov, m1v, audio m4a, etc.; realplayer applies to real company's formats, such as video rm, rmvb, audio ra, etc.; windows media player applies to Microsoft's formats, such as video wmv, rmvb, audio ra, etc. realplayer applies to real company's format, such as video, rm, rmvb, audio ra, etc.; windows media player applies to Microsoft's format, such as video wmv, audio wma, etc. But now the players are compatible with each other. But now players are compatible with each other a lot of phenomena, such as mpeg series will generally be installed. But dvd decoding format currently quicktime is not recognized.